The world of English in the palm of your hand. These apps will boost your skills.

Whether you already speak some English or are just starting out, you’ve probably got a powerful tool to help you reach the next level of proficiency: your phone. But with so many phone apps for English learners, how do you find the right app for your needs? We consulted three experts and asked for their advice.

Heidi Howland, a program officer at the U.S. State Department’s Office of English Language Programs, recommends the American English app created by her employer: “There are millions of people who might not have access to technology other than their basic phones; this app serves customers that smartphone apps can’t.”

Kenneth Beare teaches English as a second language (ESL) in Portland, Oregon, and is the resident ESL expert at About.com, a site offering information on a range of subjects. His top picks are Conversation English, Travel English and English at Work: “All three have engaging storylines. They’re adapted to modern English usage, rather than academic English.”

Kelly Roell is a Tampa, Florida–based author and resident test-preparation expert at About.com. She cites Living Language, busuu and Duolingo: “Living Language and busuu get a lot of good press…and I like Duolingo’s engaging interface.”